Plate type heat exchanger



Jan. 15,. 1957 A. H. WAKEMAN 2,777,674

PLATE TYPE HEAT EXCHANGER Filed May 1953 5 Shests-Sheet 1 Jan. 15, 1957A. H. WAKEMAN 2,777,674

PLATE TYPE HEAT EXCHANGER Filed May 29, 1953 5 Sheets-Sheet 2 Jan. 15,1957 A. H. WAKEMAN 2,777,674

PLATE TYPE HEAT EXCHANGER Filed May 29, 1953 5 Sheets-Sheet 3 I BY%VENTR. 4714M! viii Jan. 15, 1957 A. H. WAKEMAN 2,777,674

PLATE TYPE HEAT EXCHANGER Filed May 29, 1953 5 Sheets-Sheet 4 XINVENTOR. d /g2? 5. %%W

Jan. 15, 1957 A. H. WAKEMAN PLATE TYPE HEAT EXCHANGER 5 Shee ts-Sheet 5Filed May 29. 1953 Wars? IN V EN TOR E Pig/5% W oo pg/f?? c 2 PLATE TYPEHEAT EXCHANGER Alden H. Wakeman, Lairemills, Wis., assignor to TheCreamery Package Mfg. Company, Chicago, iih, a corporation of lllinoisApplication May 29, 1Q53, Serial No. 353,264

7 Claims. (Cl. 257-245) This invention relates to heat exchangers andmore particularly to a plate heat exchanger of a type adapted primarilyfor use in commercial dairies, breweries and other food and beverageprocessing plants.

Because of the inherent nature of most dairy products to be readilysusceptible to numerous harmful bacteria and also due to the fact thatone or more of such dairy products are normally included within thedaily diet of most individuals, the dairy industry, as a whole, has beenmost conscientious in its efforts to protect the public health and meetthe needs of the public by striving to produce dairy products which aremore wholesome, healthful, and delectable in character and which readilymeet the standards regarding purity as set forth by municipal, State,and Federal agencies. By reason, therefore, of the scrutinizedactivities of the dairy industry in producing and processing itsproducts, the costs of dairy operation and the equipment requiredtherefor are generally well above the average for comparable industries.

In a plate heat exchanger, for example, which in the dairy industry isutilized in the heating, cooling and pasteurization of milk and milkproducts, and which apparatus is the subject matter of this invention,it is essential that the apparatus may be readily disassembled forthorough cleaning, usually once a day or after each run, be durable andeffective in operation, and be of compact and simple constructionrequiring only a minimum floor area for proper operation.

It is one of the objects, therefore, of this invention to provide aplate heat exchanger which successfully meets the most rigid ofmunicipal, State, and/ or Federal public health regulations, is durableand highly efiicient in operation, compact and simple in construction,and is easy to service and maintain.

It is a further object of this invention to provide a plate heatexchanger whose capacity may be varied over a wide range to accommodatevariations in the fluidity and quantity of the products being circulatedtherethrough.

It is a still further object of this invention to provide a plate heatexchanger which is capable of producing a greater heat exchange undergiven conditions of plate area, temperature difference, and pressuredrop than had heretofore been attained in apparatus of this type,thereby requiring fewer number of plates to produce a given result whichin turn reduces the cost of the equipment.

It is a still further object of this invention to provide a plate heatexchanger wherein the flow of the product and/or the heat transfermedium between the various plates is at a uniform rate substantiallyacross the entire face of the plates, thereby eliminating stagnant flowareas and minimizing the precipitation and deposit upon the plates ofsolids carried by the product and/ or heat transfer medium whichcomplicate the cleaning of such plates.

It is a still further object of this invention to provide a plate heatexchanger wherein the individual sheet metal plates are of suchstructural formation that their press drawnfabrication does not set upany internal stresses 2,777,674 Patented Jan. 15, 1957 which would causebuckling, warping, or deforming of the plates thereby assuring uniformlytight gasket pressure when the plates are in pressed assembled relationwith respect to one another and facilitating the cleaning of the plateswhen disassembled.

It is a still further object of this invention to provide heat exchangeplates wherein each of the plates is uniformly supported by the adjacentplates over a substantially large area, when the plates are assembled,thereby minimizing the possibility of the plates diaphragming withrespect to one another and restricting certain of the flow passages whenthe heat transfer medium is circulated between the plates under a highpressure.

Further and additional objects will appear from the description,accompanying drawings and appended claims.

In accordance with the preferred embodiment of this invention asdescribed herein, a plate heat exchanger is provided comprising aplurality of thermal conductive plates assembled in face-to-facerelation with intermediate marginal gaskets, wherein each plate includesa center portion adapted for contact on one surface with a heat transfermedium flowing thereover, and on the opposite surface with a second heattransfer medium, and inlet and outlet portions for the circulatingmedium communicating with the center portion. The center portion carrieson both surfaces thereof means protruding therefrom which extend in acurvilinear direction across said center portion to effect turbulence ofthe circulating heat transfer mediums.

For a more complete understanding of this invention reference should bemade to the drawings wherein:

Figure 1 is a fragmentary perspective view of the improved plate heatexchanger shown in a partially disassembled relation.

Fig. 2 is a front elevational view of one of the ungasketed heatexchange plates shown in Fig. 1;

Fig. 3 is a front elevational view of one of the gasketed heat exchangeplates shown in Fig. 1;

Fig. 4 is an enlarged fragmentary back elevational view of the heatexchange plate shown in Fig. 3;

Fig. 5 is an enlarged fragmentary side elevational view taken along line5-5 of Fig. 3;

Fig. 6 is an enlarged fragmentary front elevational view of the gasketedheat exchange plate which contacts the terminal header seen in Fig. 1;

Fig. 7 is a left side elevational view of the heat exchange plate shownin Fig. 6;

Fig. 8 is a fragmentary enlarged front elevational view of thecorrugated portion of the heat exchange plate, shown in Fig. 3, inoverlying relation with respect to the corrugated portion of the heatexchange plate, shown in Fig. 2;

Fig. 9 is a diagrammatic view of the corrugated plate portions shown inFig. 8; the upper portion of the diagrammatic View indicating only thecontacting portions of the corrugations, and the lower portion of thediagrammatic view indicating only the flow ways defined by the points ofcontact between the corrugations of adjacent plates;

Figs. 10 and 11 are fragmentary sectional views taken along lines 101tland 11l11, respectively, of Fig. 8;

Fig. 12 is a sectional view taken along line 1212 of Fig. 3;

Fig. 13 is an enlarged fragmentary sectional view of the marginalportions of a plurality of the heat exchange plates, shown in Figs. 2and 3, arranged in assembled pressed relation;

Fig. 14 is an enlarged fragmentary sectional View taken along line 1414of Fig. 3;

Fig. 15 is similar to Fig. 14, taken along line 15-45 of Fig. 6; and

V matically in Fig. 16.

Fig. 16 is a diagrammatic view of a section of the heat exchange plates;solid and dotted lines indicating respectively the direction of flow oftwo heat transfer mediums between the heat exchange plates.

Referring now to the drawings and more particularly to Fig. 1, a portionof a plate heat exchanger 20, in partially disassembled relation, isshown which in this instance comprises an elongated support member 21,one or more terminal headers 22 mounted on said member 21 for slidablemovement longitudinally thereof, and a plurality of heat exchange plates27 and 28 mounted in face-to-face relation on member 21 and likewiseslidable longitudinally thereof. Guide members, not shown, disposed inparallel relation with memberzfl, are provided for engaging the lowerend ofeach of the plates27 and '28. The support member 21.. and guidemembers are supported at opposite ends by upright frame members, notshown, one of which is normally designated a stationary header.Anadjustable presser plate, not shown, is mounted on the other framemember and cooperates with the stationary header to effect pressing of aplurality of terminal headers 22 and heat-exchange plates 27 and '28therebetween to form a plurality of heat exchange plate sections 26,oneof which is shown diagram- In aheat exchanger 20 used forpasteurizing dairy products, three platesections usually designated theregenerative, heating, and cooling sections are normally utilized.

The terminal header 22, as shown in Fig. 1, functions as'a spacerbetween adjacent plate sections 26, and is provided at its. upper endwith a yoke or hanger 23 which embraces the opposite sides of thesupport member 21 and terminates in a roller 24, the latter engaging theupper edge 25 of memberjZl. The member 21, in this instance, issubstantially triangular in cross section. The terminal header 22 isusually provided with one or more ports 22' formed therein which areadapted to communicate with certain of the passageways formed betweenthe plates 27, 27a, and 28, when the latter are in assembled pressedrelation. The function of the terminal headers will become more apparentin the discussion to follow hereinafter.

The heat exchange plates.2 7 and 28, shown more'clearly in Figs. 3 and2, respectively, re fabricated preferably from sheet metal material suchas high grade stainless steel and each plate comprises a corrugatedcenter portio'n'30' and end portions 31' and 32 which are separated by"the center portion 30. The end portions 31 and '32 are each providedwith acentrally disposed recess 33 which is adapted to accommodate aportion of supporting member 21 and the guide members, not shown, whenthe apparatus is assembled; The recess 33 forms a pair oftalonshapedfingers 33a which engage the sloping sides of supporting member 21. Theedge of. each end portion, adjacent the'recess 33, is bent over aslightamount to form a stifiem'ng flange 33b to compensate for the relativelythin gauge sheet material used in fabricating the plates. Plates 27 and28, as shown in Figs. 3 and 2,'respectively, each have four apertures,A, B, C and D, two of'which are formed in'each of the end portions 31and 32. All of theapertures are of uniform size and when the plates27'and-28 are'in assembled relation, the

. corresponding apertures on the plates are, adapted'toalign withrespectto one another, to form conduits through which'the heat transfer mediumsmay flow. Thenumber of apertures in the end portions 31 and 32 of eachof the plates 27 and 28 may vary according to the location of theparticular plate within the assembled plate section 26, as seen moreclearly in Fig. 16. In the diagrammatically shown section 26, see Fig.16, the direction of flow of the heat transfer mediums, in thisinstancedesignated milk and Water, between the various plates of the section isshown "in full and dotted "lines respectively. It will be noted in Fig.'16 that plates 27 and 28 are alternately arranged Fwithin "the sectio'nand that one 'of the heat transfer mediums flows on one side and theother heat the edge of the plate and .is adapted to engage a portion ain assembled relation With' respect to one another.

1 aportion 34 of the gasket 34 in a manner, as seenin includes, withinthe delimited area, apertures A and D and defines the area over whichone of theheat transfer mediums is caused to circulate. Apertures B andC, in this instance, are completely encircled by gasket portions 3%which effect sealing off-of these apertures with respect to thedelimited area of gasket portion 34a and thereby permit one of the heattransfer mediums to by- ,ass the area delimited by gasket portion 34a.cessed trough 34c is formed in gasket 34 between gasket portions 34a and34b and is adapted to prevent the heat transfer mediums from becomingmixed or contaminated by one another in case a partof gasket portions.34a and 34b should become ruptured. In the event that a rupture shouldoccur in either end portion 31 or 32of the plate, the heat transfermediummilk or water-will fiow into trough 34c and escape out along theelongated sides of the plate and be readily detected, thereby facilitating location of the ruptured gasket when the apparatus is assembled.A delta-shapedprotuberance 34 d is formed in the gasket at the mouth ofthe trough 34c adjacent of the adjacentpla-te 28, when the plates 27 and28 are The protuberance 34d gives added support to the assembled platesat a point near one of the apertures and thereby eliminates thepossibility of the plates diaphragming with respect to one another whenthe heat'transfer medium is circulated under high; pressure through theapparatus. Gasket portion 34a, as seen in Fig. 3, is spaced from theends of the corrugations, formed in center portion 30,-

so as to provide a narrow marginal passage 35 which, when the plates areassembled, is adapted to accommodate protuberances 36 formed about themarginal por-.

tion 28a of plate 28, as seen more clearly in Fig. 13.

. Disposed within the area of plate i27, delimited by gasket portion34a, and adjacentapertures A and D are a plurality of protuberances v37which, when the plates are assembled, are adapted tocontact thecorresponding portion on the adjacent plate 28 positioned in frontthereof. The protuberances 37 have a dual function;

first, they give added support to the platesfadjacent the apertures, andsecondly, form pockets or dimples on the back side of plate 27 which areadapted to. accommodate Fig. 14. The accommodated gasketportions 34,which take the form of lugs, are adapted to prevent :the gasket,

adjacent the apertures A through D, from Spreading or moving relative tothe metallic. plate on which it is mounted when the heat transfermediumis flowing through the aperture under high pressure. The gasket 34is formed preferably of a plastic material, such as rubber, which may bereadily vulcanized directly on the sheet material during the fabricationof the latter and which will not be deleteriousl yalfected by-either ofthe heat transfer mediums The portions of the gasket 34 disposed on thefront and backsurfaces of the plate'27 are preferably integral with oneanother.

' It is to be noted that each of the gas'keted plates 2711 which, asheretofore mentioned, is theend plate of a'section and contacts theadjacent surface of either the terminal header'22, presser plate, or.stationary header the latter two n0tshown -has all of the apertures Athrough .Dfonthe side of the plate-which .is in contact with one of-saidadjacent surfaces, completelygasketed with respect to one anotherbygasket portions 34b,,=as

A reseen in Fig. 6. The reason for gasketing all of the apertures onthis side of the plate 27a is to prevent any of the heat transfer mediumbecoming trapped between the plate 27a and the adjacent surface of theheader 22, presser plate, or stationary header. It is also to be noted,in Fig. 7, that the portion of the gasket 34 disposed on this side ofthe plate 27a is not of the same thickness as the portion of the gasketdisposed on the other side of the plate. The reason for this thicknessdifferential between the portions of the gasket on either side of plate27a is that the thinner gasket engages the adjacent uncorrugated surfaceof the header 22, presser plate, or stationary header and permits thecorrugations formed in the center portion 30 of the plate to contact theadjacent surface, as well. The remaining gasketed plates 27 in a section26 have the portions of the gasket 34 of uniform thickness on both sidesof the plate 27, as seen in Fig. 14.

It is to be noted in Fig. 13 that, when the plates 27 and 28 are inassembled pressed relation, the protuberances 36 formed in the marginalportion of plate 28 do not contact the adjacent marginal space 35 ofplates 27 disposed on either side of plate 28. Thus, the heat transfermedium may circulate over the protuberances as well as around them. Thefunction of the protuberances 36 is to act as flow-retarders, therebypreventing the heat transfer medium from flowing at a more rapid ratealong the sides of the center portion 30 than in the middle thereof.This flow-retarding action is caused by the great turbulence effected bythe protuberances along the sides of the center portion. it will benoted that only every other one of the protuberances 36a or 36b projectin the same direction from a particular side of the plate 28. As aresult of the increased turbulence within the marginal space 35 of plate27, no depositing or accumulating of particles of the heat transfermedium occurs on the plate adjacent the gasket portion 34a, as hadgenerally occurred in prior heat exchangers. This depositing,particularly in the case of milk, is frequently referred to as milkstoning which materially increases the difliculty of cleaning the platessubsequent to disassembly of the apparatus.

The longitudinal edges of the center portion 30 of plate 28, as seen inFig. 13, are bent in substantially the same direction to form a pair offlanges 33, between which a gasketed plate 27 nests, when the plates arein assembled relation. The flanges 38 prevent outward spreading of thegasket portion 34a when the plates are pressed together and therebyreduce the possibility of gasket failures. In addition, a furtherstrengthening or stiffening effect for the plate 28 is obtained byreason of the flanges 38.

Both plates 27 and 28, when fabricated, have the corrugations 40 formedin center portions 30 thereof extending in a curvilinear directionacross the plates. The incurvate corrugations 40 are formed in the sheetmaterial by subjecting the latter to a high pressure between formingdies. By reason of the incurvate contour of the corrugations and thevery high pressure required for their formation, it is believed thatthere is an actual flow of the metal throughout the corrugated portionof the plate which results in no internal stresses remaining within theplate subsequent to forming, which might cause the latter to buckle,warp, or deform when the plate has been released from an assembledpressed position with respect to other plates. Thus, the plate 27 or 28,because of its freedom of any locked-up internal stresses, will alwaysassume a planar position, thereby facilitating cleaning, assembling, anddisassembling of the apparatus 20.

While the corrugations 40 are shown in this instance to be continuousand to extend thwartwise of the plates 27 and 28, it is to beunderstood, of course, that these corrugations might be formed ofinterrupted segments and extend in a direction other than that shownwithout departing from the scope of this invention. In the plates 27 and28 shown in Figs. 3 and 2, respectively, the corrugations thereof arearcuate in shape. When the plates are in assembled relation, as seen inFigs. 8 and 9, the direction of curvature of the corrugations of eachsucceeding plate is opposite from the one preceding it, thus the centerportions 30 of adjacent plates contact one another at several points asseen in the lower half of Fig. 9. These points of contacts define flowways 41, 42a and b, 43a and b, 4411 and b, 45a and b, and 46a and bwithin the passageway formed between adjacent plates. The number of flowways will vary depending upon the radius of curvature of thecorrugations 46. The widths of the flow Ways decrease uniformly from thelongitudinal center of the center portion outwardly to the marginalspace 35 of plate 27 or the corresponding point on plate 28. It willalso be noted that the actual contacts between adjacent plates are merepoints but because of the acute angles of crossing of the contactingprotuberances at the middle of the center portions, wider restrictionsto flow result, as indicated in Fig. 9. No point of contact between theplates occurs at the longitudinal centerline because of the fact thatthe ridges 46a and valleys 40b of the corrugations 40 of one plate arenot superimposed with respect to one another as seen more clearly inFig. 10, but instead are ofiset approximately one-third the distancebetween adjacent ridges 49a of a plate. Nothwithstanding the fact thatthe flow ways 41, 42a and b, 43a and b, 44a and b, 45a and b, and 46aand b are not uniform in width, a uniform rate of flow of the heattransfer medium between the adjacent plates is obtained which isbelieved to be due to the fact that the ridges 49a and valleys 4% withinflow ways 41 are disposed substantially at right angles to the directionof flow within the flow way 41, thus causing more resistance to flowthan is caused by the ridges and valleys of the corrugations withinouter flow ways 46a and b which are substantially less than a rightangle with respect to the direction of flow. A further contributingfactor to this uniformity of flow rate is due to the fact that therestricted areas about the points of contact defining flow way 41 are ofgreater size than those about the points of contact defining the otherflow ways. Thus, by reason of the turbulence caused by the largercontact areas, the effective width of flow way 41 is reduced to asubstantially greater extent than flow ways 46a and b.

By varying the number of apertures A, B, C, orD in each of the plates27, 28, or 270, the numbers of streams of water or milk flowing in onedirection between adjacent plates to form a pass, as commonly referredto in this art, may be varied to suit a particular condition. In theplate section 26, shown in Fig. 16, the flow passages for the milk andwater each constitute a two-stream pass and a three-stream pass system.

Thus, it will be seen that a plate heat exchanger has been providedwhich is simple and compact in construction, may be readily cleaned andserviced, requires less plates because of the greater heat transfercapacity of the novel plate design, and readily meets the rigidstandards of cleanliness as set forth by various municipal, State, andFederal agencies.

While a particular plate heat exchanger has been shown above, it will beunderstood, of course, that the invention is not to be limited thereto,since many modifications may be made, and it is contemplated, therefore,by the appended claims, to cover any such modifications as fall withinthe true spirit and scope of this invention.

1 claim:

1. In a plate heat exchanger capable of disassembly through which a heattransfer medium circulates, a pair of removable complemental thermalconductive plates, said plates being arranged in contacting face-to-facerelation to form a plurality of elongated substantially parallelpassageways therebetween for such medium, the widths of said passagewaysbecoming progressively narrower from the center passageway outwardlytoward the sidewise spaced passageways each plate comprising anelongated center portion having a plurality of elongated crescenticcorrugations formed therein, said corrugations being arranged insubstantially coextensive relation and extending crosswise of saidcenter portion and'transverse to the direction of flow ofsuchcirculatingmedium' to effect turbulence of the latter, the directionofcurvature of the corrugations on one plate being opposite from thedirection of curvature of the corrugations on the other plate wherebyonly segments of the corrugations of said plates are in contact with oneanother when said plates are in assembled relation, and define saidpassageways the portions of the corrugations of said complemental'plates disposed between said contacting corrugation segments definingsaid center passageway being in staggered spaced relation with respectto one another, when said plates are assembled, to efiect uniform rateofflow of such medium through all of said passageways, and meansformed oneach plate and disposed on opposite sides'of said center portion andcommunicating witlrrsaid passageways to' effect circulation of suchmedium therethrough;

2. A plate heat exchanger capable of disassembly throughrwhich a heattransfer medium circulates, comprising a pair of removable thermalconductive plates arranged in contacting face-to-face relation to form aplurality of elongated substantially parallel passageways for thecirculating medium, each plate having the con tacting face thereofprovided with a plurality of elongated crescentic corrugationsextcndingcrosswise of the plate face and substantially transverse to thedirection of flow of the circulating medium to efiect turbulence of thelatter; the direction of curvature of the corrugations of one platebeing substantially opposite from the direction of curvature of thecorrugations of the other plate whereby only segments of the oppositecorrugations are in contact with one another, the magnitude of themedium flow resistance effected by the contacting segments of said opposed corrugations becoming progressively smaller from the centerpassageway toward the 'sidewise'spaced passageways formed between saidpair of contacting plates.

7 3. A plate heat exchanger capable of disassembly through which a heattransfer medium'circulates, com :prising a pair of elongated thermalconductive plates arranged in contacting face-to-face relation to form aV plurality of longlu'diually extending passageways for the circulatingmediurmeach plate having the contacting face thereof provided with aplurality of elongated crescentic substantially coextensive corrugationsextending crosswise of the plate face and substantially transverse tothe direction of flow of the circulating medium to efiect turbulence ofthe circulating medium and to maintain said plate'in substantiallyplanar configuration when in disassembled relation; the direction ofcurvature of the corrugations of one plate being substantially oppositefrom the direction of curvature of the corrugations of the other platewhereby only segments of the opposed corrugations are in contact withone another, the widths of the passage ways defined by said contactingsegments becoming progressively narrower from the center passagewayoutwardly toward the sidewise spaced passageways.

4. The exchanger recited insclairn 2 wherein one of I said pair ofcontacting plates is provided with a marginal gasket delimiting thecorrugated center portion thereof and a similar corrugated centerportion on the other of said pair of plates; saidsecond plate having thecontacting face thereof provided with a marginal :flange adaptedtoaccommodate and encompass portions of said marginal gasket. f r

5. The exchanger recited in claim 2 wherein one of saidpair ofcontacting plates is provided with a one-piece marginal gaskethaving afirst section thereof delimiting the contacting face on one side of saidplate and having a second section thereof integral with said firstsection and delimiting the'contactingface on'the other side of said,plate.

6. The exchanger recited in claim 2, wherein one of said pair ofcontacting plates is'providedwith a plurality of marginalprotuberances'spaced endwise from said crescentic corrugations, theprojection of said marginal protuberances being less than theprojectionof said crescentic corrugations whereby said marginal protuberancesare-not in contact with the otherof said pair ofcontacting plates. 7.111a plate heat exchanger capable of disassembly through which a heattransfer medium' circulates, comprising a plurality of removable thermalconductive plates:

arranged in contacting face-to-face relation to} form a plurality ofelongated substantially parallel passageways I for the circulatingmedium between adjacent plates, each: plate having the contacting facethereof provided with a plurality of elongated crescentic corrugationsextending crosswise of the plate face and substantially transverse tothe direction of flow of the circulating medium'to 'efiect turbulence ofthe latter; the direction of curvature of the corrugations of one platebeing substantially opposite from the direction of curvature of thecorrugations of the adjacent plate whereby only segments vof theopposite corrugations are'in contact with one another, the magnitude ofthe medium flow resistance effected by the contacting segments ofsaidopposedcorrugations becoming progressively smaller from the centerpassageway outwardly toward the sidewise spaced passageways; onlyalternate plates of said plurality of plates being provided with amarginal gasket having one segment thereof afiixedtoone contacting facethereof and delimiting the corrugated area thereof and a similar area onthe contacting surface of the adjacent plate, and a second section ofsaid gasket integral-with said first section andaffixed to the oppositecontacting face-of said plate and delimiting the corrugated area thereofand a similar area on the contacting surface of the adjacent plate; theremaining alternate plate being provided with amarginal flangeencompassing a portion. of the gasket section of one of theadjacentgasket plates.

' OTHER REFERENCES Serial No. 402,669, Manz tA. P. (3. published May 25,1943. r a

